Internally displaced Congolese line up to collect water in an impromptu refugee camp in Kibati. Congo is one of the poorest nations in the world, but many other so-called "developing" are catching up to the world's wealthiest. Picture: APSource: AP

WHEN it comes to knowledge about the world's population, most of us are pretty clueless.

So says Hans Rosling, professor of global health at Sweden's Karolinska Institutet, who is calling for a "reality check" on widely-held fears about overpopulation and resource shortages.

"If for each question I wrote each of the possible alternatives on bananas, and asked chimpanzees in the zoo to pick the right answers, and by picking the right bananas, they'd just pick bananas at random. But the Brits did even worse," he said.

Chimpanzees know more about the world than humans do. Picture: APSource: AP

The problem, according to Prof Rosling, is that most people's ideas about population, developing countries and extreme poverty are based on information that is decades out of date.

An example of one of the questions in the test:

In the year 2000 the total number of children (age 0-14) in the world reached two billion. How many do UN experts estimate there will be by the year 2100?

a) 4 billion

b) 3 billion

c) 2 billion

d) 1 billion

If you answered a) 4 billion, you picked the most popular response. But you're also wrong. The correct answer is c) 2 billion.

With this in mind, here are five big myths that Prof Rosling has debunked.

Soaring population growth

In the past decade the global total number of children (aged 0-14) has reached about 2 billion, and UN population experts predict it won't rise any more this century. There has been a drop in the average number of babies being born to women, which has been caused by better female education and more access to contraception.

Because we've reached "the age of Peak Child", the world's rapid population growth will slow down in the second half of the century.

Residents march during an anti-government protest in the upper middle class neighbourhood Barra da Tijuca in Rio de Janeiro, Brazil. The majority of the world’s population live in countries like Brazil, which sits in the middle on the scale of wealth to poverty. Picture: APSource: AP

Developing v developed worlds

The division between "developing" and "developed" nations was very clear cut 50 years ago. But these days the line is much more blurry.

Much has changed - even in the past decade - and the so-called "developing" countries have been catching up. While there is still a big division between wealthy and poor nations, the majority of the world's population live in middle-of-the-road countries such as Brazil, Mexico, China, Turkey and Thailand.

Life expectancy

Average life expectancy in the world is currently 70 years. This is up from the average life expectancy of 60 years in the 1960s. But the current rate is much better news because it applies to the majority of the world's population. The 1960s figure was skewed because there was high life expectancy in wealthy nations and short life expectancy in poor nations.

Female education

Women worldwide are more educated today than they were 50 years ago, but there is still an education gap between men and women. But exactly how big is it?

Currently men aged between 25 and 34 have had eight years of schooling on average. Women aren't far behind, with an average of seven years of schooling.

Kenyans make their way through the narrow streets in the Kibera slum in Nairobi. Just over one billion live in extreme poverty. Picture: APSource: AP

Extreme poverty

Extreme poverty - defined as an income of less than $1.25 per day - is well and truly on the decline. There were two billion people in extreme poverty in 1980, now there are just over one billion. This means six out of seven billion people are not living in extreme poverty.

And evidence is suggesting that the remainder could get out of extreme poverty in the next few decades. This will "mainly be through their own hard work," Prof Rosling said. "But it will only happen if they receive, from their governments and from the world at large, the focused help they need to stay healthy, get educated and increase their productivity."

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